X-ray tube.



No. 842,875. PATBNTED FEB. 5, 1907.

' M. EHRHARDT;

X-RAY TUBE.

APPLIOATIOK FILED 00T.18. 1904.

UNITED sTArns ijn rnNT OFFICE."-

MYLIUS EHRHARDT, F BERLIN, GERMANY:

x-nAY TUBE.

To all whom it may concern.-

Be it known that I, MYLIUS EHRHARDT, manufacturer a subject of the Kin of Prussia, German m eror, residing at erlin, in the Kingdom 0 Prussia, German Empire,

have invented .certain new and useful Improvements-in X Ray Tubes, of whlch the.

ollowing is a specification. v

Thisfmvention' relates to an. improved Rontgen tube ada ted for use with medical invest ations. T 's tube is provided with means or concentrating and conducting the cathode-rays to a certa n definite direction; further, with means for regulating the vacuum, with means for con ueting heat from the interior of the tube by cooling the antica'thode, and, finally, with means for connecting the tube to ane ectric circuit.

The-ob ect of my invention is'to do away with the annoyance of the ph sician and of the patient by rays leaving .t e' tube in an undesired direction or by sparks; and further aobjects of the invention are the increase of the handiness and the certain effectof the tube.

There exist already Rontgen tubes in which a tube of normal lass or metal is shoved over the anticatho e in order to col- 'leet the cathode-raysand to conduct them into a certain definite direction. Collectingtubes of this kind have not roved usefu since the tube that consists 0 normal glass collects thecathode-rays only in an imporfeet manner, whereas the metal tube collects the rays, it is true, but gives itself rise to the development of gases, 'whereby the tube when practicallyemplbyed becomes soon ineffective.

The inventor-has found that atube manufactured from lead-glass is very well suited to concentrate and direct the cathode-rays, without, however, possessing I the drawbacks of the tubes hitherto employed. As lead-glass when sub'ected to the action of cathode-rays easil meits at a place situ atedabove the an-. ticat ode, the lead-glass tube is protected at that place by a plate consisting of a non-eonducting material, such as china and they like,

the plate being attached to'the anticathode.

In order to make my invention more clear, I refer to the accompanying drawings, in which similar letters denote similar parts throughout the several views, and which Figure l is a side view of my'miproved Specification of Letters Patent. Application filed-October 18,1904. am No. 228.999.

- away the Patented rep. 5, 1907.

showing the same in an upright position. Fig. 2 is a plan of the tube, the anticathode being directed against the beholder; and Fi s. 3 and 4 re resent two details, which wil be more full hereinafter.

Refcrrin to said figures, lie the anticathode, 2 the eadlass tube shoved over said anticathode, and 3 is the lateprotecting the lead-glass tube against eing melted, as before stated. The lead-glass has an orifice 4 for allowing of the entrance of the cathoderays, and the end f the tube is open in order to permit of conducting the rays against the body to be lighted.

The lead-glass tube 2 prevents the cathoderays from distributing 1n thedirection of the hemis here arranged in frontof the anti- Rontgen tube,

y described catho e 1 and to escape from said hemi I sphere and to molest either the physician or t 1 e patient. The rays are collected within the lead-glass tube 2 and are conducted against a limited space of the patients body,

so asto light that space intensely and deliver'ing very distinct photos. This, however, occurs only, so long as the Rontgen tube is st1ll'softthat is to say, contains only a low vacuum. becomes hardthat is to say, if its vacuum gets high-also the lead-glass tube would be unable to retain the rays and it would be necessary to decrease the vacuum in known manner, which would be troublesome when made .during the lighting of the patient. In order to prevent also m such a case the physician and the patient againstthe effect If the Rontgen tube during use of rays escaping in an unintended direction,

I employ a metal lining 6, Figs. 1 and 2, consistin of metal powder or of thin sheet meta securedin .any appro riate manner to the outer surface of the tu e. The rays meeting this lining are retained by the same,

as they cannot penetrate said lining, and

therefore the space outside the latter in so .far. as it is protected by the same is secured against the rays, as is also the the atient in an adequate measure. T e metal lining 6 should not be extended very near to the electrode 7, as otherwise s arks strike across the remaining s ace irectly from said electrode to the metahlin- The lead-glass tube 2 with the protectingplate 3 on one part and the metal lining 6 on physician and" the other part support one another with respect to their effects; but inspite of this each of the two arrangements may be employed per se.

\ In order to soften the Rontgen tube which i has become hard during the lighting, I

make use of a vacuum-regulating device, which is known per se and the action of which consists in interrupting the circuit leading to the cathode, so that the current is conducted through an auxiliary cathode against a substance adapted to develop a gas and let the same get lnto the interior of being brought about s arks get over from the main conduit to an into the cathode or to and into the auxiliary cathode so long as is necessar to establish the new circuit. These spar s expose the physician to dan ger and make the atient nervous.

In my improve Rontgen tube the regulating device in order to prevent the arising of sparks is arranged in such a way that when the connection between the main conduit and the cathode is interrupted the current passes at once through the. auxiliary cathode, which is constantly connected with the main conduit. Of course the auxiliary conduit must be arranged in such a manner that its distance from the anodes is greater than the distance between the cathode and the anodes.

The improved vacuum-regulating device is represented in Figs. 1 and 3 of the accompanying drawing.

The currentpasses from the main conduit 8 to the cathode7 through the wire 9 and the contact-pieces 10 and 11. Around the wire 9 is wound a spiral spring 12, which is supported at its upper end by the contact-piece .10 and at its lower end by a small perforated metal plate 13 or by a simply bent piece of wire connected, by means of a conduit, with the auxiliary cathode 14, arranged in a side tube 15, the interior of which is not connected with the interior of the Rontgen tube.

When the wire 9 is removed from the tube, so that the contact between .the pieces 10 and 11 is interrupted, Fig. 3, the current passes at once from the conduit 8 to the auxiliary cathode 14, through the wire 9 and the plate 13, and from this plate. to the piece of wire, 17 along the glass bulb 16, which communicates with the interior of the Romgen tube and contains caustic potash or anpieces 10 and 11 is under the action of the spring 12 again established. No sparks can arise while the current is thus diverted.

To operate the switch, I employ instead of the small non-conducting rod itherto used a cord 27 bound to the wire 9 and consisting also of a non-conducting materi'alfor instance, silk. The physician may easily keep this cord in his hand in order to regulate the vacuum. also during the lighting, if such re lation should prove necessary. This cor is.

obviously more advantageous than the said rod, which oftenti a" es is not at hand ust when The anticathode 1 and the being needed. inner space of the lead-glass tube 2 are more highly heated in consequence of the concen-' tration of the cathode-rays in said tube, whereby it is It ade requisite to conduct away the excess of heat. This may be eiiected by the known cooling devices using water; but these devices are, in fact, not advantageous,

becaii sethey increase the weight of the Rorrtgen tic-be by the water-condt it and n". ake the tube less handy. There is also the risk that in the case of the water-conduit becon. ing untight the water establishes a conducting connection between the Rontgen tube and the hand of the physician, so as to expose the latter to the danger of receiving electric shocks;

To do away with'these drawbacks, I employ an anticathode having a sleeve-like configuration. (See Fig. 4.) i This sleeve is shoved over the glass tube 18, serving as a carrier for the anticathode, and is secured to the sarre by rrans of a nietal pin 19, placed into a n'etal tube 20,. cast into the glass tube 18. This tube has a filling 21 consisting of pieces of Iretalsuch as iretal chips, 1r etal leaves, the so-called flarretta, and the like and is closed by a stopper 22, consistin of conglobate tin-foil. The'heat arising Within the in terior of the tube is conducted away from the anticathode to and into the open air through the metal pin 19, thenietal tube 20, the me- .tallic filling 21, and the stopper 22. A certain decrease of tenv perature is brought about also by the fact that every partie ie of the metal filling is surrounded with air. There is also prbvided a particular mode offastening the binding-pieces 24 of the anode 23,

said 1r ode of fastem'n being also suited for the binding-pieces o the cathodes. Said binding-pieces were up to now' provided with binding-pieca'and Iinsert into said cavity, a; coinparatively'strong bow 24, connected with the thin wire 26, after which gypsumiis filled into the said cavity. In the case of the cav- 1 1. In a Rontgen tube of 'thekind described, the combination with an anticathode '1, of -a lead-glass tube 2 inclosing said anticathode, a lateral opening 4 provided in said tube and situated between the anticathode and the end opening 5 of the tube, and a plate 3 also located within the said. tube and vsituated about opposite to said lateral opening; for the purpose was described. I

2. In a Rontgen tube of the kind described, the combination with a cathode 7 and an anticathode 1, of a lead-glass tube 2 inclosing said anticathode, a lateral opening 4 provided in said tube and situated between the anticathode and the end opening5 of the tube, opposite to saidcathode, a plate 310- cated also within the said tube and situated in a line with said lateral opening and the cathode, and a metal lining surrounding said end opening at some distance therefrom, for the purpose as described.

3. In a Rontgen tube of the kind described,

' the combination with the cylindrical portion of the Itontgen tube, 'ofanother tube 15located in said cylindrical portion, the interior of this tube having no connection with the interior of the Rontgen tube; a glass bulb located at the end of said inner tube near to the ball-like portion of the Rontgen tube and communicating with the same, a substance adapted .to develop a gas when being electrically heated and contained in said bulb, an auxiliary cathode 14 arranged within said side tube, a conducting-wire connected with said auxiliary cathode, and a switch connected with the main conduit, substantially as and for the purpose described.

the combination with the Rontgen tube proper, of a side tube 1 5, the interior of which has no'connection with the interior of the said Rontgen tube, a glass bulb 16 located at one end of the side tube and communicating with the interior of the Rontgen tube, a substance adapted to develop a gas when being electricall tained in said bulb, an auxiliary cathode 14 arranged within said side tube, aconductingwire connected with saidauxiliary cathode, and a switch 9 connected with themain conduit, substantially as and for the purpose described.

5. In a Rontgen tube of the kind described, I

the combination with the ball-like portion and the cylindrical portion ofthe Rontgen tube, of an anticathode located in the firstmentioned portion, a lead-glass tube 2 inclosing said anticathode, a lateral opening 4, providedin'saifd tube and situated between 1 the anticathode and the end opening 5 of the tube, and a plate 3' also located 'within the said tube and situated about opposite to said lateral opening; a tube 15 located in the cylindrical portion, the interior of this tube having no connection with the interior of the Rontgen tube; a glass bulb located at the end of said inner tube near to the ball-likeportion "of the Rontgen tube and communi-r eating with the same, a substance adapted.

to develop a gas when being electrically heated and contained in said bulb, an auxiliarycathode 14 arranged within said sideheated and con-' 4. In a Rontgen tube of the kind described, I

tube, a conducting-wire connected with the main-conduit, a switch 9, and a cord 27, consisting of a non-conducting material and being constantly connected with said-switch,

substantially as and for the purpose as described. r In witness whereof I have hereunto set my hand in presence of two witnesses.

. MY LIUS EHRHARDT. Witnesses:

WoLnEMAR IIAUPT, HENRY HASPER. 

